The present invention relates generally to receptacle connectors, and more particularly, to receptacle connectors that are used to make connections between an integrated circuit (xe2x80x9cICxe2x80x9d) package having numerous contacts, such as a BGA or LGA contacts, and a printed circuit board having numerous contacts pads formed thereon.
FIG. 7 illustrates a conventional connector having numerous terminals 300 embedded in its insulative housing 301. In use, the housing 301 is sandwiched between an IC package (not shown) and a printed circuit board 302. Each terminal 300 of the connector typically includes a contact arm 304 that is applied against a selected contact pad 303 of the circuit board 302, and a contact 305 integrally formed to the contact arm 304 for touching a selected counter contact, typically a spherical or land-shaped contact of the IC package. The connector housing 301 has retainers 306 formed therein which hold terminals 300 in the housing 301 in such a way that each contact 305 is resilient enough to yieldingly move, or sink, when applied to the counter contact.
The presence of these retainers 306 formed in, or as part of the terminal housing 301 prevents the reduction of the connector housing thickness. The conventional receptacle connector of FIG. 7, therefore, is too thick to be used in personal computers, which have been getting smaller and thinner. Also disadvantageously, the conventional receptacle connector allows its contact arm ends to be stained with flux in soldering to conductor pads 303. Also, soldering material is allowed to attach to its contact arm ends in the form of whiskers.
The present invention is directed to an improved receptacle connector that overcomes the aforementioned disadvantages.
Accordingly, it is a general object of the present invention is to provide a receptacle connector having a reduced thickness.
Another object of the present invention is to provide a low-profile receptacle connector for BGA or LGA applications, the connector including a thin housing in the form of a socket, the socket having a plurality of cavities formed therein, a plurality of terminals disposed in the cavities, each of the terminals having a flat terminal body portion with at least two opposing edges, the terminal including a terminal retention arm extending in one direction from one of the two terminal body portion edges and a terminal retention stub extending in a second direction from the other of the two terminal body portion edges, the terminal flat body portion having shape that permits it to be held in place within a molding cavity such that molding material from which the connector housing is formed may flow around the terminal retention arm and stub to retain the terminal in place within the connector housing, thereby eliminating the need for forming terminal retainers in the connector housing associated with each connector housing cavity.
A further object of the present invention is to provide a terminal for use in reduced-height connector housings, and the terminal including a flat body portion, the body portion having at least two opposing edges, a retention arm extending away from the terminal body portion in one direction and along one of the two edges thereof, a retention stub extending away from the body portion in a second direction and along the other of the two edges thereof, and a contact arm extending away from the terminal body portion in a cantilevered fashion for making contact with an opposing contact pad on a circuit member to which the connector housing is mounted.
A still further object of the present invention is to provide a terminal as described above, but with the terminal having two retention stubs at two opposing ends of the terminal body portion, each of the retention stubs extending into the connector housing and serving to retain the terminal in place within the connector housing, the terminal having a pair of contact arms extending away from the terminal body portion in a cantilevered fashion for making contact with opposing contact pads on circuit members flanking the connector housing.
To attain these and other objects, the present invention provides a receptacle connector for connecting an IC package with numerous contacts such as a BGA or LGA type contacts to a circuit board having numerous contact pads disposed thereon, the connector including an insulative housing interposed between the IC package and the circuit board, the housing having a plurality of terminals embedded therein for making connections between the IC package contacts and the contact pads of the circuit board. This structure is improved by forming the terminals in a desired manner such that each terminal includes comprises a flat trunk, or body portion and at least one cantilever-like contact arm integrally connected to the flat body. The terminals are preferably arranged in the connector housing with their flat bodies parallel to a plane of the terminal housing, and are preferably supported by the terminal housing in a manner so that the molded portions of the housing overhangs the opposite longitudinal and lateral edges of the terminal flat bodies.
The terminals may take one or two embodiments. In one embodiment, a retention arm extends upwardly from the plane of the terminal body portion at an angle thereto, and a retention stub extends away from the terminal body portion in the same plane as the body portion. Both the retention arm and the retention stub are held in place within a molding cavity so that the connector housing material may be molded around them to anchor the terminals in place within the connector housing. In this embodiment, the flat body portion is exposed on one side of the connector housing cavity that communicates with the terminal, so that an element, such as a solder ball may be attached thereto.
In another embodiment of the invention, two retention stubs extend in the same plane as the terminal body portion and extend away therefrom. The terminal is bent upon itself to form the retention stubs so as to define a cantilevered contact arm that extends away from the terminal at the flat body portion and at the portion where the terminal is retained in the connector housing, and in this second embodiment of the invention, two such cantilevered contact arms are thereby defined that extend from the terminal in opposite directions so that the connector using such terminals may be interspersed between two circuit members, or circuit boards.
With this arrangement, the connector terminals are firmly held in place by molded portions of the connector housing, thereby eliminating the forming of such retainers as in conventional receptacle connectors. Thus, the thickness of the receptacle connector can be reduced. This structure also advantageously prevents the staining, or contamination, of the terminals and their contacts with soldering flux. It also prevents the attachment of hairs, whiskers or strands of solder from adhering to the terminal contacts.
In the area where the cantilevered contact arms are formed, each terminal may have a xe2x80x9cUxe2x80x9d-shaped joint formed at its body-to-contact arm transition area where the terminal is bent upon itself, and the molded connector housing overlies these xe2x80x9cUxe2x80x9d-shaped joints to retain the terminals in place. The body portion of the terminal may also serve as a contact by supporting a selected spherical contact of the IC package, such as a solder ball, and permitting it to be applied to the center of the terminal body portion. Each terminal may have two cantilever-like contact arms integrally connected to the opposite lateral edges of the trunk.
These and other objects, features and advantages of the present invention will be clearly understood through a consideration of the following detailed description.